1. Field of the Invention
The present invention relates to thin film graphitic systems and, more specifically, to a method of growing graphite oxide layers.
2. Description of the Prior Art
Graphene is a semimetal that includes a single atomically thin sheet of graphite. Ultra-thin graphitic layers on silicon carbide include one or more graphene sheets on a silicon carbide substrate. Graphene has a potential use as a material for microelectronics. However, for graphene to be useful in microelectronics applications, it must be configurable as a semiconductor. One way to accomplish this is to pattern the graphene to make nanoscopically narrow ribbons, since graphene becomes semiconducting with a band gap that is approximately inversely proportional to the width of the ribbon.
It is known that ultra-thin graphitic layers form on silicon carbide crystal substrates when the silicon carbide substrate is heated in vacuum to temperatures in the range of 1100° C. to 1600° C. In this process silicon evaporates from the surface, causing the surface to become carbon rich. Carbon on the surface converts to an ultra-thin graphitic layer, which includes one or more graphene sheets, so that an ultra-thin graphitic layer forms on the silicon carbide surface.
Experiments have demonstrated that the properties of ultra-thin graphitic layers grown on silicon carbide crystals are essentially similar to those of a single graphene sheet. It has also been demonstrated that ultra-thin graphitic layers on silicon carbide crystals can be patterned using microelectronics lithography methods to produce electronically functional structures. Consequently, as for single graphene sheet, ultra-thin graphitic layers grown on silicon carbide crystals can be used as an electronic material.
For graphene and multilayered graphene to become semiconducting so that it can be used for electronic applications, the multilayered graphene must be patterned into ribbons that are narrower than about 20 nm. Producing ribbons that are narrower than 20 nm requires non-standard nanofabrication techniques that may be difficult to implement for large-scale production.
Also, a graphene sheet that is in contact with the silicon carbide substrate, which is called the interface layer, acquires an electronic charge, whereas the other layers are substantially uncharged. Due to this charge, the conductivity of the interface layer is particularly large and therefore carries most of the current when voltages are applied to multilayered graphene ribbons. While this conducting interface layer has advantages for some applications, it is disadvantageous for many electronic device structures.
Therefore, there is a need for a method of converting a portion of a thin film graphitic structure into a semiconductor using existing lithographic techniques.
There is also a need for a silicon carbide-based graphitic layer in which the conductivity of the interface layer is reduced.